BOTANICAL GAZETTE. 25 
Amphigenous or epiphyllous; perithecia small, .0025 in. to 
.003 in.; appendages 8 to 12, mostly curving upward, but not 
fascicled, | to 2$ times the diameter, 3 to 4 times parted, tips 
somewhat swollen. 
These forms all have septate appendages and do not differ 
materially in their spores and asci. The differences that do ap- 
pear are chiefly in the size of the perithecia and in the number 
and length of the appendages. As these vary more widely in 
perithecia from the same leaf than do the averages of the ditfer- 
ent forms, there seems no ground for their separation into dis- 
tinet species, unless we allow more weight to the difference of 
host plant than is usual in the Erysiphet; but they should be 
considered as belonging to a large, widespread, variable species, 
comparable with Erysiphe lamprocarpa, Lev. and Microsphera 
penicillata, Lev. 
Saccardo, in his ‘‘Sylloge Fungorum,” gives Podosphera 
Oxyacanthe (DC.) De Bary, with “appendages 8 to 10, about 
equal to the perithecium,’”’ on species of Crategus in Europe, 
Algeria, etc. ur form on Crategus agrees well with this de- 
scription, except that the appendages are sometimes a little 
longer, which we have seen to be an unimportant character. 
He divides the forms that have usually been referred to P. 
Kunzei, Lev. between P. myrtillina, Kunze, having “6 to 10 
appendages, three times the diameter, radiating divergently,” 
on Vaccinium in Europe; and P. tridactyla, ( Wallr.) sary, 
having “ few, 3 to 7 appendages, three times the diameter, rising 
in a parallel bundle,” on species of Prunus in Europe and North 
merica. 
Two European specimens in my collection on Prunus do- 
mestica and Prunus Padus show the peculiar character of P. tri- 
dactyla, having the few appendages clustered at the summit of 
the perithecium and rising in a parallel bundle. A part of the - 
perithecia from the specimen on Prunus Americana (see above), 
approached this form rather closely, but in all the other speci- 
mens examined the appendages are more or less widely divergent, 
thus seeming to bridge the difference between this form and PF. 
myrtillina Kunze’. 
The form on Spirea has been described by Howe in Vol. 5, 
of the Torrey Bulletin, under the name of P. minor. ; 
8 Erysiphe Oxyacanthe DC., was the earliest name given 
: ‘Having never seen specimens on Vaccinium, I can not, of course, say that 
this is to be included with the other forms, but there is nothing in the descrip- 
tion by which it can be separated. 
